Pre heat oven to 350°. Line a cookie sheet with parchment paper.
Combine the flour, salt and baking powder in a medium bowl and set aside.
Cream together the butter and sugar, beating it until it is fluffy.
Add the eggs, one at a time, the lemon juice and lemon zest. Beat until they are fully incorporated into the batter.
Add the flour mixture and beat until all of the flour disappears.
Transfer the dough to the prepared baking sheet and form into a log that is about 3-4" wide by about 3/4" high. Use your hands to flatten the dough and shape it. If the dough is sticky you may need to flour your hands.
Bake the biscotti for 30 minutes. Remove the cookie sheet from the oven and allow it to cool for about 10 minutes.
Using a sharp serrated knife, cut the cookies into ½" slices and lay them on the cookie sheet, cut side up.
Reduce the oven temperature to 300°. Bake the cookies for 10 minutes. Turn them over and bake for 10 more minutes. Remove the biscotti from the oven and cool completely.
While the biscotti are cooling, place the chocolate chips in a medium sized, microwave safe bowl. Microwave for 30 seconds, remove from the microwave and give them a stir. Continue to do this until the chocolate is completely melted and smooth.
Decorate the biscotti with the white chocolate any way you like. Dip the ends, bottoms or drizzle the chocolate on the biscotti. Lay them on a wire rack to dry.
The finished biscotti can be stored in an airtight container for 2 weeks or frozen for up to 3 months.